valve job???
- Thread starter Big_Al
- Start date
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moper
Well-Known Member
$500 for 5 angle, Serdi equipment. Doesn't include guides which have to be perfect if you want to get all the benefits of it.
madscientist
Banned
Who says 5 angles is better?
What most people do not realize is, nearly every single modern automotive engine from about the 1940s all the way through now has at least a 3 angle job on the seat.
That said, the shop I use gets 150 for a standard 3 angle competition valve job with 3 angles on the seat and valve cut on a serdi machine. Never have asked about a 5 angle as I don't think it makes a noteworthy difference.
That said, the shop I use gets 150 for a standard 3 angle competition valve job with 3 angles on the seat and valve cut on a serdi machine. Never have asked about a 5 angle as I don't think it makes a noteworthy difference.
madscientist
Banned
Depends on several things.
Never on an exhaust. Always a radius on those.
The biggest factors are underhead radius of the valve, combustion chamber shape and seat angle.
moper
Well-Known Member
IMO - yes. But it can be a little misleading. As Mad said - the exh side really only needs an accurate, concentric set of 3 angles. On the intake side the 5 angle takes the 3 angle and adds a throat cutting angle which performs about 80% of a mild bowl blend, and just as important adds an unshrouding angle in the chamber which performs that operation much more accurately than one can by hand. It's important that the actual transitions between angles are concentric.
So in short, and focussing only on the actions of the cutters (rather than talking about back cutting the valves themselves), the 5 angle adds a basic bowl porting/blending and chamber work on the valve job. It's more economical than paying for hand labor, and more repeatable and accurate than doing it by hand. So to me it's a no brainer.
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